I think almost all contacts with the Klingons ended in war. There was the first encounter, battle. Everything in TOS was a fight except for 1 episode where they wanted to fight. Then in TNG we were at an uneasy peace, in DS9 is was a strong peace, then war, then peace again (right?) and Voyager's encounter with the Klingons was a battle too, I believe. I think that about sums up the Klingon history on Star Trek.